MDAC files missing?

I have a Dimension E510 with Windows XP.  I had uninstalled something and in doing so, I think I accidently removed files needed for other programs.  Since the uninstall, I have not been able to open some software programs and I have not been able to restore to previous time.  Each time I select a date to restore to and my computer reboots, it says that it was unable to restore to the date selected.  With Corel, I looked up some troubleshooting and found I may be missing the MDAC files.  I am not able to download them becuz the version of MDAC files are only able to be installed with the OS disc, which I do not have.  Can someone tell me if reinstalling the system to the factory settings will reinstall these MDAC files?  If so, how do I go about reinstalling the system to the factory settings without the OS disc?